CAD/CAM/CAE

Hi Hinal,
It is great to see your interest in interior designing but unfortunately, learning only AutoCAD will not suffice to become a professional in the industry. The interior design courses are specially designed to equip you with certain skills like design principles, color therapy, space planning and industry standard software. It gives a thorough exposure to students on different kinds of projects to prepare them as a professional. It will also make you aware about various materials and products. Taking up an internship under a trained and successful interior designer is, of course, a cherry on the top.

You are already doing what needs to be done. CAD and the solid edge is enough along with interior designing.

You definitely can by taking classes at different timing. It depends on you how much stress you can take. Also, will your mind be able to capture and retain the different commands of the two software. Saying so, which of the two courses is better depends on which industry you go into next. In automobile industry, catia is used more, which in construction, autocad is used more as per my knowledge. All the best.

CAD after 12th will be not of much use. You are advised to do CAD course after Diploma in Engineering or Graduation in Engineering.